Nokia OS (NOS) is an informal name for the operating system in many Nokiamobile phones. These are informal names, there is no such product or trademark, though the term "Nokia OS" is used in official Nokia communications. Officially it is referred as ISA (Intelligent System Architecture) platform. It is a proprietary platform for Nokia's internal use only. It is licensed to no one else. No direct application programming interface (API) is provided, but most ISA phones can be programmed with Java Platform, Micro Edition (Java ME). It is sometimes called the "domestic OS".